<!DOCTYPE HTML>
<html>
<head>
<style>
	* { font:12px Arial; }
</style>
</head>
<body>
<table>
<script>
	for (var i = -5; i <= 10; i++) {
		document.write('<tr><td id="a' + (i / 2) + '"></td><td><span id="s' + (i / 2) + '" style="background:#DDD;letter-spacing:' + (i / 2) + 'px">letter-spacing</span></td><td id="c' + (i / 2) + '"></td></tr>');
	}

	window.onload = function() {
		function $(id) { return document.getElementById(id); }
		if (!window.getComputedStyle) {
			window.getComputedStyle = function($target){
				return $target.currentStyle;
			};
		}
		for (var i = -5; i <= 10; i++) {
			document.getElementById("a" + (i / 2)).innerHTML = (i / 2);
			document.getElementById("c" + (i / 2)).innerHTML = getComputedStyle(document.getElementById("s" + (i / 2))).letterSpacing;
		}
	}
</script>
</table>
</body>
</html>
</body>
</html>